sorry, i can't help directly, but some things i noticed abaout your problem.

First: n my mind the thread would be better placed in Install / Compile forum.
Secound: Your FreeCAD package is very old. We are on 0,17 13509 now, wich is released as stable since about two weeks.
Third: I reed about nearly the same problem with an Arch based system (and installing with AUR), but don't remember that someone can help... So maybe it's better you ask in a Manjaro Forum to.

I'm on obensuse and have also problems to install FC on regular way, but the AppImage works very fine, maybe it works on Manjaro to.
FreeCAD_0.17.13509.glibc2.17-x86_64.AppImage is the actuall release, you can download here: https://github.com/FreeCAD/FreeCAD/releases